Update {virtual,override,final} to follow C++11 style.

components/dom_distiller/core/distilled_page_prefs_android.h

Index: components/dom_distiller/core/distilled_page_prefs_android.h
diff --git a/components/dom_distiller/core/distilled_page_prefs_android.h b/components/dom_distiller/core/distilled_page_prefs_android.h
index bcb96c2aaf5ecc9da8e1b56391c4a1e0726e14e9..de3928eccecf18b4d4a11f1a7dfc4c0e7bedb058 100644
--- a/components/dom_distiller/core/distilled_page_prefs_android.h
+++ b/components/dom_distiller/core/distilled_page_prefs_android.h
@@ -40,9 +40,9 @@ class DistilledPagePrefsObserverAndroid : public DistilledPagePrefs::Observer {
   virtual ~DistilledPagePrefsObserverAndroid();
 
   // DistilledPagePrefs::Observer implementation.
-  virtual void OnChangeFontFamily(
+  void OnChangeFontFamily(
       DistilledPagePrefs::FontFamily new_font_family) override;
-  virtual void OnChangeTheme(DistilledPagePrefs::Theme new_theme) override;
+  void OnChangeTheme(DistilledPagePrefs::Theme new_theme) override;
 
   virtual void DestroyObserverAndroid(JNIEnv* env, jobject obj);